Relationship between various maternal conditions and lactic acid dehydrogenase activity in umbilical cord blood at birth

Background: Lactic acid dehydrogenase (LDH) is a valuable marker for some of the most important diseases in newborns and the plasma LDH activity in newborns correlates well with conditions such as asphyxia. If LDH should be considered as a useful tool also in obstetric care, key factors associated with maternal health before and during pregnancy which could affect umbilical cord LDH activity need to be known. The aims of this study were to explore relationships between selected maternal conditions and arterial lactic acid dehydrogenase activity (aLDH) in umbilical cord blood at delivery. Methods: A prospective observational study was conducted at Sodersjukhuset, Stockholm, Sweden. Included in the study were 1247 deliveries, and cord blood samples from each were analyzed for aLDH. Background, delivery and neonatal data were collected from the medical records. Results: Higher median values of aLDH were found (P=0.001) among women with chronic disorders not related to pregnancy but there was no increased frequency of high aLDH levels (>612 μ/L, P=0.30). No difference in aLDH was identified between infants born to women with pregnancy-related disorders compared with healthy women, neither in median values, nor in high values (>612 μ/L, P=0.95). Conclusion: Newborn infants born to women with non-pregnancy-related chronic disorders had a somewhat higher median value of aLDH in cord blood at delivery. The influence of common maternal conditions and diseases on umbilical cord arterial LDH levels is small compared to the increase reported in fetal distress and several other critical conditions in the newborn.